This invention relates to a magnetic multilayered film having a high saturation magnetic flux density and a high permeability. More particularly, the present invention relates to a magnetic head for use in magnetic disk apparatus, magnetic tape recorders (VTR's), etc., and relates also to a magnetic multilayered film suitable as a material for a magnetic core of such a magnetic head.
In order to prevent magnetic saturation of such a magnetic head during recording, the material for the magnetic head is required to have a high saturation magnetic flux density. Also, from the aspect of efficiency of reading with the magnetic head, the material for the magnetic head is required to have a small coercive force and a high permeability.
In order to provide magnetic materials having a high saturation magnetic flux density required for the magnetic head of the kind described above, alloys containing Fe as an essential constituent are now being developed. However, among these alloys, those having a saturation magnetic flux density higher than 1.8 T (tesla) have a large coercive force and are not suitable for use as the material for the magnetic head. Therefore, in an effort to provide a magnetic material having a small coercive force and a high permeability, a multilayered film structure including a plurality of magnetic material layers laminated together with a plurality of intermediate layers of, for example, SiO.sub.2 has been proposed, as discussed in Japanese Patent Application Laid-open No. 52-112797 (JP-A-52-112797) based on U.S. patent application serial No. 662,198 filed on Feb. 26, 1976, now U.S. Pat. No. 4,049,522.
However, a multilayered film structure in which a plurality of layers of an alloy containing Fe as an essential constituent are laminated together with a plurality of intermediate layers of a nonmagnetic metal oxide, for example, SiO.sub.2 or Al.sub.2 O.sub.3 has had such a problem that its coercive force is not sufficiently decreased depending on the composition of the alloy of Fe. Further, such a multilayered film structure has had another problem that its saturation magnetic flux density is greatly decreased, because the nonmagnetic metal oxide such as SiO.sub.2 or Al.sub.2 O.sub.3 is porous, and the Fe alloy deposited directly on the intermediate layer of SiO.sub.2 or Al.sub.2 O.sub.3 includes many defects such as vacancies.